Vehicular transportation having protection against improper operation



June 20, 1967 M F|NK VEHICULAR TRANSPORTATION HAVING PROTECTION AGAINST IMPROPER OPERATION Filed Sept. 14, 1965 2 Sheets-Sheet 1 CONTROL INVENTOR WITNESSES:

Milton Fink ATTORNEY June 20, 1967 FlNK 3,326,326

VEHICULAR TRANSPORTATION HAVING I'ROTEC'llON AGAINST IMPROPER OPERATION Filed Sept. 14, 1965 2 Sheets-Sheet 2 FIG. 4.

|RR33 R33 U 23 I CONTROL SYSTEM OF PATENT 2,565,632 WITH MODIFICATIONS United States Patent VEHICULAR TRANSPORTATION HAVING PRO- TECTION AGAINST IMPROPER OPERATION Milton Fink, Rochelle Park, N.J., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Sept. 14, 1965, Ser. No. 487,225 Claims. (Cl. 18739) This invention relates to a transportation system and it has particular relation to a vehicular transportation systern wherein a vehicle is arranged to serve vertically spaced landings or floors.

Although the invention may be incorporated in vehicular transportation systems arranged to serve horizontallyspaced landings, it is particularly suitable for a system arranged to serve vertically-spaced landings. For this reason the invention will be described as applied to an electric elevator system. The elevator system may be either of the attendant-operated type or of the automatic passenger-operated type.

In a modern elevator system it is the practice to connect an elevator car to a counterweight by means of one or more ropes or cables passing over a traction sheave. The system also includes motive means coupled to the traction sheave. This motive means may be energized for the purpose of rotating the traction sheave and thereby applying traction forces to the ropes or cables for the purpose of moving the elevator car in vertical directions.

For protective purposes a safety conventionally is mounted on the elevator car. Should the elevator car reach an excessive speed the safety is automatically set to grasp the guide rails which are employed for guiding the elevator car in a vertical direction. In this manner the elevator car is brought to a safe stop. A similar safety may be employed for the counterweight associated with the elevator car. Each safety is set by means of a governor located in or near the machine room which is usually a penthouse room. When the elevator car or the counterweight reaches an excessive speed the associated governor also acts to deenergize the motive means associated with the elevator car.

Selfenergizing safeties advantageously are employed in elevator systems. An example of such a safety will be found in the Rissler Patent 2,581,297 which issued I an. 1, 1952.

Under some conditions, such as a dragging safety shoe, or where the governor rope gets caught on building steel or brackets a self-energizing safety may set even though the associated elevator car or counterweight does not reach a speed sufiicient to operate its governor. If the counterweight self-energizing safety sets because of drag, the associated governor does not operate, and the motive means continues to rotate the associated traction sheave. The resulting slippage of the ropes or cables relative to the traction sheave may produce sufficient heat to distort and crack the sheave and may actually break the sheave. Such slippage and heat damages the cables and the sheave which will require replacement.

In accordance with the invention the setting of a selfenergizing safety due to drag results in deenergization of the motive means which is coupled to the traction sheave. In a preferred embodiment of the invention the motion of the motive means and the motion of the elevator car and/or counterweight are sensed. If these are not properly related the motive means is deenergized.

It is therefore an object of the invention to provide an improved vehicular transportation system having means for preventing undesired operation of motive means employed for moving the vehicle.

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It is another object of the invention to provide an improved vehicular transportation system having means for deenergizing the motive means employed for driving the vehicle when the speed of such motive means and the speed of the vehicle are not properly related.

Other objects of the invention will be apparent from the following description taken in conjunction with the accompanying'drawings wherein:

FIGURE 1 is a schematic view with parts shown in side elevation, with parts shown in perspective and with parts broken away of an elevator system embodying the invention;

FIG. 2 is a schematic view with circuits shown in straight-line form of a control system suitable for the elevator system of FIG. 1;

. FIG. 3 is a schematic view with circuits shown in straight-line form showing modified control circuits which may be incorporated in the system of FIG. 2;

FIG. 4 is a schematic view with circuits shown in straight-line form illustrating a further modification of control circuits which may be incorporated in the system of FIG. 2;

FIG. 5 is a detailed view in perspective showing a speed-responsive switch employed in the system of FIG. 2; and

FIGS. 6 and 7 are schematic views with parts in perspective illustrating further modifications of the invention.

Referring to the drawings FIG. 1 shows an elevator system which comprises a sling R1 which is mounted in a conventional manner by means of guide shoes R3 for movement in a vertical path. In accordance with conventional practice the guide shoes R3 are secured to the sling and slidingly engage continuous vertical guide rails R5 in order to constrain the sling R1 for movement in a vertical path.

Adjacent its lower end the sling R1 has a safety device R7 which may be operated to grasp the guide rails R5 for the purpose of retarding the descent of the sling and stopping it. Such operation of the safety device R7 may be effected through a governor rope R9 which has its ends secured to the sling. The governor rope R9 passes around the wheel Rlla of a governor R11 at the top of the hoistway and a tensioning wheel, R13 at the bottom of the hoistway in a conventional manner. It will be understood that the wheel Rlla is rotated in accordance with movement of the sling R1.

When the rate of movement of the sling exceeds a predetermined value, centrifugally-operated weights in the governor R11 operate a brake to engage the governor rope. This brake may be so adjusted that it applies a substantial braking force to the rope which permits the rope to slip therethrough when the force applied by the sling to the governor rope exceeds the braking force of the governor. Furthermore, the governor may be provided with an electrical switch R33 which opens when the governor brake is applied for the purpose deenergizing the motive means employed for operating the sling. The governor also may act to close a switch R34 when the speed of the sling R1 exceeds a predetermined value. The sling R1 may be employed as the elevator counterweight.

A sling RRl also is provided for supporting an elevator car A. This sling is associated with guide shoes RR3, guide rails RRS, safety device RR7, governor rope RR9, governor RRll, tensioning wheel RR13, and electrical switches RR33 and RR34 which are similar to the corresponding components associated with the counterweight sling :and which are identified by the same reference characters except for the addition of prefix letters R.

The elevator car A may be moved between the floors or landings of a building in any conventional manner. In FIG. 1 it will be noted that a traction sheave 11 has an elevator rope passing thereabout. One end of the rope 10 is secured to the sling RR1 whereas the remaining end of the rope is secured to the counterweight sling R1. The rope passes around an idler or secondary sheave 11A in a manner well understood in the art. Rotation of the traction sheave 11 is effected by means of an elevator motor 14 which is energized through a motor control from a source of electrical energy. 7

The safeties R7 and RR7 are assumed to be of the self-energizing type. An example of such a self-energizing safety will be found in the aforesaid Rissler patent.

In order to simplify the presentation of the invention as much as possible it will .be assumed that the control circuits of the Santini et al. Patent 2,565,632, which issued Aug. 328, 1951, are employed in the present case. The Santini et al. patent shows control circuits for two elevator cars with partial circuits for two additional cars. Inasmuch as the invention here presented may be discussedadequately as applied to a single elevator car only the circuits associated with the elevator car A of the Santini et al. patent will be here considered. FIG. 2 of the present application reproduces the left-hand half of FIG. 3 of the Santini et :al. patent with certain additions shown in dotted enclosures. In addition, the running relay M and the inductor holding relay G of the Santini et al. patent have additionalsets of make contacts M4 7 and G3 added thereto. Except for these changes the circuits employed for the elevator car herein discussed are similar to those employed for the elevator car A of the Santini et al. .patent. The reference characters shown in the Santini et al. patent also are reproduced in the present FIG. 2 to identify the same components. To facilitate the following discussion the'reference characters identifying similar components in the present FIG. 2 and in FIG. 3 of the Santini et al. patent are listed as follows:

A-Eleva-tor car Ddown reversing switch E-slow-down inductor relay F-stopping inductor relay G-inductor holding relay GA-generator armature L+3 and L3-direct current supply conductors M--running relay Uup reversing switch Vhigh-speed relay W-up direction preference relay X-down direction preference relay 10cable 11-sheave 1-4motor 15-brake 22-loop circuit 23s'afety devices As previously noted a set of make contacts G3 is here added to the inductor holding relay G, and a set of break contacts M4 is added to the running relay M,

Inasmuch as FIG. 1 shows a secondary sheave 11A associated with the traction sheave 11 the rope 10 in FIG. 2 has an angular position differing slightly from that shown in the corresponding figure of the aforesaid Santini et al. patent.

A suitable device 52 is provided for sensing rotation of the motor armature 14A and its shaft 13. In a preferred embodiment of the invention this device takes the form of a drag-magnet sensing device. A shown more clearly in FIG. 5 the shaft 13 carries an electro-conductive disc or armature 53 which may be constructed of a material such as copper or aluminum. A lever 54 is mounted for rotation about a shaft 55 which extends in a direction parallel to the shaft 13. At its upper end the lever 54 carries a permanent magnet 56 having its poles adjacent but spaced from a vertical surface of the disc 53, A weight 57 at the lower end of the lever 54 biases the lever 54 towards a vertical position.

The lever 54 carries a cam 58 which coacts with a cam follower 59. This cam follower forms part of a spring leaf 60 having its upper end attached to a fixed support 61 and having a pair of contacts 63 secured to its lower end. As shown in FIG. 2 when the parts are at rest and deenergized one of the contacts 63 is urged by the weight 57 into closing engagement with a set of fixed contacts 63-1. When the motor armature 14A and the disc 53 start to rotate, eddy current forces are developed between the disc 53 and the permanent magnet 56. These forces urge the cam 58 away from the cam follower 59 and permit the resilient leaf 60 to move one of the contacts 63 into closing engagement with a set of fixed contacts 63-2. During this operation the contacts 63-1 are opened.

Turning now to the center part of FIG. 2 it will be noted that the right-hand terminal of the running relay M is connected to the conductor L-3 through the safety devices 23, the contacts 63-1 and the governor-operated switches R33 and RR33. The governor-operated switch R34 is connected across the contacts 63-1.

In practice an elevator car is designed to operate at what is termed a rated or contract speed which may fall in the range of feet per minute to 1800 feet per minute. For present purposes it will be assumed that the elevator car A is designed to operate at a contract speed of 500 feet per minute. This corresponds to the high speed of the elevator car with the contacts V1 closed. The contacts 63-2 are designed to be closed when the rate of rotation of the motor exceeds a predetermined value below contract speed such as a value corresponding to an elevator car speed of 30 feet per minute. The contacts R34 are assumed to close when the elevator car exceeds a speed below the contract speed such as 10 feet per minute.

The operation of the system shown in FIG. 2 now may be considered. Inasmuch as the basic operation of the system is largely shown in the aforesaid Santini et al. patent reference to such patent may be made for a more detailed discussion of the common components of the two systems. The present discussion will be directed primarily to the changes in the operation which are introduced by the present invention.

Let it be assumed that the elevator car A is at the bottom landing and that it is to be started in the up direction. As will be evident from a consideration of the aforesaid Santini et al. patent the up direction preference relay W is energized and picked up under these conditions.

When the car attendant closes the switch SW the following circuit is completed L+3, SW, SW1, W1, F1, STU, U, M, 23, 63-1, R33, RR33, L-3. Upon completion of this circuit the up reversing switch U and the running relay M are energized and the elevator accelerates in the up direction in the manner discussed in the aforesaid Santini et al. patent.

As soon as the elevator car speed exceeds 10 feet per minute the contacts R34 close without any immediate effect on the operation of the system.

As soon as the speed of the elevator car A exceeds 30 feet per minute the contacts 63-1 open. However, inasmuch as the contacts R34 are now closed, the opening of the contacts 63-1 has no immediate effect on the opera tion of the system.

Let it be assumed next that as the car continues upwardly a dragging of the counterweight safety results in the setting of this safety. Inasmuch as the motor continues to rotate at a rate in excess of that represented by a car movement of 30 feet per minute the contacts 63-1 remain open. However, the counterweight is now stationary and the switch R34 consequently opens. Inasmuch as the switch R34 and the contacts 63-1 are open the running relay M and the up reversing switch U are deenergized. Consequently the motor 14 is deenergized and the brake 15 is applied in the manner discussed in the aforesaid Santini et al. patent. The stopping of the motor 14 prevents subsequent damage to the traction sheave 11 and to the cable or rope 10.

Let it be assumed next that the elevator car while traveling up in a normal manner is to stop at a landing. The stopping sequence is initiated in the same manner as in the aforesaid Santini et al. patent. As the car speed drops below 30 feet per minute the contacts 63-1 close. As the car speed drops below feet per minute the contacts R34 open. However, these contact operations have no .effect on the stopping of the car.

Should the counterweight or elevator car overspeed one .of the switches R33 or RR33 opens to deenergize the running relay M and the up reversing switch U. These components stop the elevator car in the manner discussed in the aforesaid Santini et al. patent.

A modification shown in FIG. 3 is similar to that discussed for FIG. 2 except for the circuit controlling the up reversing switch U, the down reversing switch D and the running relay M. For this modification the up reversing switch U is provided with an additional set of break contacts U7 and the high speed relay V is provided with additional set of break contacts V2. In FIG. 3 the righthand terminal of the running relay M is connected to the conductor L3 through the safety device 23,- the break contacts U7 and V2 in parallel, and the switches R33 and RR33. The parallel circuit is bridged by a circuit containing the switch R34 and the contacts 63-2 in series.

Let it be assumed that with the modifications shown in FIG. 3 incorporated in the control system the elevator car is to be started up from the bottom landing. When the car attendant operates the switch SW, an energizing circuit for the up reversing switch U and the running relay M is completed throughthe safety devices 23 and the contacts U7 and V2 in parallel. Although the contacts U7 open promptly the contacts V2 of the high speed relay V2 remain closed as the car starts to accelerate. As the car accelerates to a speed in excess of 10 feet per minute the make contacts R34 close. When the car thereafter accelerates to a speed in excess of 30 feet per minute the contacts 63-2 close. Subsequently the high speed relay V picks up to open its break contacts V2. However, such opening has no effect at this time on the up reversing switch U and the running relay M for the reason that these components remain energized through the switch R34 and the contacts 63-2 both of which are now closed.

If the safety on the counterweight now sets due to drag on its guide rails, the car speed drops below 10 feet per minute and the governor switch R34 opens to deenergize the up reversing switch U and the running relay M. Con sequently, the motor 14 is deenergized in the manner set forth in the aforesaid Santini et al. patent to prevent damage thereafter to the traction sheave 11 and the cable or ropes 10. As the motor stops, the contacts 63-2 reopen but such reopening has no immediate effect on the operation of the system. Also the contacts U7 and V2 reclose but such reclosures do not have an immediate effect on the operation of the system.

The presence of the break contacts U7 introduces a directional effect. Thus, during down operation of the elevator car the break contacts U7 remain closed. Consequently openings of the contacts R34, 63-2 and V2 during down travel of the elevator car have no effect on the operation 'of the system. If this directional effect is not desired the contacts U7 may be omitted.

In the modification in FIG. 4 the system is similar to that represented in FIG. 2 except for the control of the up reversing switch U, the down reversing switch D and the running delay M. For this embodiment a relay 69 is provided having a set of make contacts 69-1 and a set 6 of make contacts 69-2. A timing relay 51 having make contacts 51-1 also is provided.

It will be noted that in FIG. 4 the right-hand terminal of the running relay M is connected to the bus L3 through the safety devices 23, the make contacts 69-2, the break contacts 51-1 of the timing delay '51 and the switches R33 and RR33. The relay 69 is connected across the conductors 'L+'3 and L3 through the switch R34. The switch R34 is shunted by a circuit containing the contacts 6.3-1 and the make contacts 69-1 in series. In addition, the contacts 63-1 are shunted by make contacts G3 of the inductor holding relay G. The make contacts 69-1 are shunted by a normally-open manually-operated switch .73.

The timing relay 51 is connected across the buses L+3, L3 through break contacts M4 of the running relay M. The timing relay also may be connected across these buses through any one of a plurality of switches k1 to k7, one

for each of the floors 1 to 17 respectively. These switches are cam operated by a cam kk. As the car passes a floor the corresponding switch is momentarily closed by the cam kk. Consequently, the cam kk is mounted on the brush carriage 17 and the switches k1-k7 may be mounted on the floor selector 16 of the aforesaid Santini et al. patent. Thus, as the car moves upwardly past the floors 2 to 7 the cam kk successively momentarily closes the switches k2 to k7.

For the operation of the embodiment shown in FIG. 4 it again will be assumed that the elevator car is to leave the bottom landing in an up direction. Inasmuch as the car is stopped at the bottom landing the break contacts M4 are'closed and the timing relay '51is energized and picked up. Before the elevator car can be started up the switch 73 must be operated to its closed condition manually to complete with the contacts 63-1 an energizing circuit for the relay 69. When energized the relay 69 closes its holding contacts 69-1 to establish with the contacts 63-1 a holding circuit for the relay. In addition the relay closes make contacts 69-2. Consequently, when the car attendant closes his car switch SW he completes an energizing circuit for the up reversing switch -U and the running relay M through the safety devices 23-, the contacts 69-2, the contacts 51-1 and the switches R33 and RR33 across the conductors L+2 and L3.

When the speed of the elevator car exceeds 10 feet per minute the switch R34 closes to establish a holding circuit for the relay 69.

When the speed of the elevator car exceeds 30 feet per minute the contacts 63-1 open. However, the relay 69 remains picked up because of the presence of the closed contacts of the switch R34.

If the safety on the counterweight should set because of its dragging on the associated guide rails the car speed drops below 10 feet per minute and the switch R34 opens to deenergize the relay 69 (it will 'be recalled that the contacts 63-1 and G3 are open). The relay 69 thereupon drops out to open its holding contacts 69-1 and its contacts 69-2. Opening of the latter contacts deenergizes the up reversing switch U and the running relay M. These components deenergize the motor 14 by a sequence which will be clear from the aforesaid Santini et al. patent. Thus, the possibility of damage to the traction sheave 11 and the cable 10 again is minimized. From the preceding discussion it will be clear that the elevator system cannot be reactivated until the manually-operated switch 73 is again operated to energize the relay 69.

If the elevator car A while running up is to stop at a landing, the inductor holding relay G will pick up to close its make contacts G3. Consequently, a holding circuit is established for the relay 69 through its holding contact 69-1 and the make contacts G3 of the inductor holding relay. Inasmuch as the make contacts 69-2 remain closed, the stopping operation proceeds in the manner discussed in the aforesaid Santini et al patent.

If desired the timing relay 51 may be employed in addition to the other modifications herein discussed. The time longer than the time required for the elevator car A to ?move continuously from one landing to the next landing in one direction of travel. As the car passes each landing the timing relay is reset or reenergized by momentary closure of one of the switches k1 to k7. However, if the safety on the counterweight should set-because of dragging, the timing relay 51 ultimately times out to open its make contacts 51-1. This assures the .deenergization of the up re- -versing switch U and the running relay M and these in turn assure deenergization of the motor 14 by the sequence set-forth in the aforesaid Santini et a1. patent.

In FIG. 6' two' modified rotation sensing devices are .disclosed. In the first device an armature 53A, a lever 54A,

. a'magnet'SGA, a weight 57A, a leaf 60A and contacts 63A andv 63A2 correspond respectively to the elements 53, .54, 56, 57, 60, 63 and 63-2 of FIGS. 2 and 5 and coact in the same way. However, in this version the armature 53A is mounted on a shaft 81 which also carries a wheel 83. This wheel 83 has its rim in engagement with the rim of the sheave .11 to rotate the armature 53A in accordance with rotation of the sheave 11. The wheel 83 may have its vrim constructed of a material establishing a good frictional engagement with the sheave, such as rubber or another elastomer.

In the second device an armature 53B a lever 54B, a

magnet 56B, a weight 57B, a leaf 60B, and contacts 63B and 63rB2- correspond respectively to the elements 53, 54, 5'6, 57, 60,63 and 63-2 of FIGS. 2 and 5 and coact in the same way. The armature 53B is mounted on a shaft 85 which alsocarries a wheel 87. This wheel is similar to the wheel 83, but has its rim positioned to engage, and be driven by, the rope 10. Thus, the armature 53B is rotated 'in accordance with movement of the rope FIG. 6 shows a circuit similar to that of FIG. 3 except thatthe contacts 63A2 and 63B2 are connected in series in place of the contacts 63-4. of FIG. 3. If the sheave 11 is rotating and if the rope 10 is moving normally the con- .tacts 63A2 and 63B2 are closed to permit energization therethrough of the running relay M. However, if the rope 10 stops because of the setting of the counterweight or'car safetythe contacts 63B2 are opened to initiate a deenergization of the motor 14. Similarly, if the motor stalls the contacts 63A2 open.

The torques developed by the magnets 56A and 56B of FIG. 6 may be arranged to act in opposition and to be balanced under normal operating conditions. Such an arrangement is shown in FIG. 7.

In FIG. 7, the armature 53A, lever 54A, magnet 56A, weight 57A, leaf 60A, contact 63A, shaft 81, wheel 83, sheave 11 and rope 10 of FIG.'6 are reproduced. The contact 63A cooperates with contacts 63A1 which correspond to the contacts 63-1 of FIGS. 2 and 4. FIG. 7 also reproduces the armature 53B, the magnet 56B and the wheel 87 of FIG. 6. However, gearing 91 is interposed between the wheel 87 and the armature 53B to reverse the direction of rotation of the armature 5313. Thus, the armatures 53 A and 53B of FIG. 7 rotate in opposite directions.

The magnet 56Bis connected to the lever 54A by means of a link 93. The parts are so proportioned that under normal conditions of operation the torques applied to the lever 54A by the magnets 56A and 56B are equal and opposite. Under these conditions the contacts 63A1 are closed.

If the car or counterweight safety sets and the rope 10 comes torest, the armature 53B stops and the torque developed by the magnet 56B drops to zero. If the elevator 'rnotor' continues to run the magnet56A develops substantial torque which is no longer balanced by that of the magnet 56B consequently 'the' contacts 63A1 open. If these contacts replace the contacts 63-1 of FIG. 4 their opening initiates the deene'r gization of the elevator motor Although the invention has been described with reference to certain specific embodiments thereof other modifications falling within the spirit and scope of the invention are possible.

I claim as my invention:

1. In a transportation system, a structure providing a plurality of landings spaced in a vertical direction, a vehicle, means mounting the vehicle for movement relative to the structure in a path having a substantial vertical component for servicing said landings, counterweight means for said vehicle for balancing at least part of the weight of the vehicle, motive means, traction means coupling the vehicle to the motive means, said motive means being effective when energized for operating through the traction means to move the vehicle relative to the structure in at least one direction along said path at a contract speed, an energizing control path for controlling energi- Zation of said motive means including a first path portion operable between an energy transmitting condition and an energy blocking condition, a first control device for operating the path portion from one to the other of said conditions of the path portion, and motion-responsive means responsive to failure of said vehicle to move above a predetermined speed which is below the contract speed of the vehicle when the motive means is energized to produce contract speed for operating the control device to maintain said energizing control path in condition to interrupt energization of the motive means.

2. A system as claimed in claim 1 in combination with a second path portion for said energizing control path operable between an energy transmitting condition and an energy blocking condition, and motion-responsive means responsive to increase in speed of the motive means above a'predetermined value which is below the contract value for operating the second path portion from one to another of its conditions.

3. A system as claimed in claim 1 in combination with starting control means for said motive means effective during a starting operation of the vehicle to complete said control path, said starting control means being ineffective to control said control path following completion of a starting operation of the vehicle.

4. A system as claimed in claim 1 in combination with stopping means for stopping the vehicle at a desired one of the landings, and means effective during operation of said stopping means for maintaining said control path in condition to maintain energization of the motive means.

5. A system as claimed in claim 1 in combination with direction means rendering said motion-responsive means effective to interrupt energization of the motive means for only one direction of travel of said vehicle.

6. In a transportation system a structure providing a plurality of landings spaced in a vertical direction, a vehicle, means mounting the vehicle for movement relative to the structure in a path having a substantial vertical component for servicing said landings, counterweight means for said vehicle for balancing at least part of the weight of the vehicle, motive means, traction means coupling the vehicle to the motive means, said motive means being effective when energized for operating through the traction means to move the vehicle relative to the structure in at least one direction along said path at a contract speed, an energizing'control path for controlling energization of said motive means including a first path portion operable between an energy transmitting condition and an energy blocking condition, a first control device for operating the path portion from one to the other of said conditions of the path portion, motion-responsive means responsive to failure of said vehicle to move above a predetermined speed which is below the contract speed of the vehicle when the motive means is energized to produce contract speed for operating the control device to maintain said energizing control path in condition to interrupt and lock out energization of the motive means, and manually-operable means for terminating said lockout by the motion-responsive means.

7. In a transportation system, a structure providing a plurality of landings spaced in a vertical direction, a vehicle, means mounting the vehicle for movement relative to the structure in a path having a substantial vertical component for servicing said landings, counterweight means for said vehicle for balancing at least part of the weight of the vehicle, motive means, traction means coupling the vehicle to the motive means, said motive means being effective when energized for operating through the traction means to move the vehicle relative to the structure in at least one direction along with said path, means for energizing said motive means for starting said vehicle means and for stopping the vehicle at a landing, and differential means responsive to the difference in speed between the motive means and the vehicle for interrupting the energization of the motive means.

8. In a transportation system, a structure providing a plurality of landings spaced in a vertical direction, a vehicle, means mounting the vehicle for movement relative to the structure in a path having a substantial vertical component for servicing said landings, counterweight means for said vehicle for balancing at least part of the weight of the vehicle, motive means, traction means coupling the vehicle to the motive means, said motive means being effective when energized for operating through the traction means to move the vehicle relative to the structure in at least one direction along with said path at a contract speed, energizing means for energizing said motive means to start the vehicle, stopping means for stopping the vehicle at a desired one of the landings, said energizing means comprising an electrical control path effective for maintaining energization of the motive means only as long as said electrical control path is continuous, said last-named path including parallel first and second arms, means for opening said first arm in response to decrease in the speed of said vehicle below a predetermined value which is less than contract speed, and means for opening said second arm in response to increase in speed of the motive means above a value which is less than the contract value.

9. In a transportation system, a structure providing a plurality of landings spaced in a vertical direction, a vehicle, means mounting the vehicle for movement relative to the structure in a path having a substantial vertical component for servicing said landings, counterweight means for said vehicle for balancing at least part of the weight of the vehicle, motive means, traction means coupling the vehicle to the motive means, said motive means being effective when energized for operating through the traction means to move the vehicle relative to the structure in at least one direction along with said path at a contract speed, energizing means for energizing said motive means to start the vehicle, stopping means for stopping the vehicle at a desired one of the landings, said energizing means comprising an electrical control path effective for maintaining energization of the motive means only as long as said path is continuous, said path including parallel first, second and third arms, means for opening said first arm in response to decrease in the speed of said vehicle below a predetermined value which is less than contract speed, means for opening the first arm in response to decrease in speed of the motive means below a predetermined value which is below contract value, means for opening the second arm in response to setting of the vehicle for movement in a predetermined direction, and means responsive to a stopping operation for closing the third arm.

10. In a transportation system, a structure providing a plurality of landings spaced in a vertical direction, a vehicle, means mounting the vehicle for movement relative to the structure in a path having a substantial vertical component for servicing said landings, counterweight means for said vehicle for balancing at least part of the Weight of the vehicle, motive means, traction means coupling the vehicle to the motive means, said motive means being effective when energized for operating through the traction means to move the vehicle relative to the structure in at least one direction along with said path at a contract speed, energizing means for energizing said motive means to start the vehicle, stopping means for stopping the vehicle at a desired one of the landings, said energizing means comprising an electrical control path eifective for maintaining energization of the motive means only as long as said path is continuous, said path including electroresponsive means having a first condition of energization wherein said path is continuous and a second condition of energization wherein said path is interrupted, and means for selectively energizing said electroresponsive means through a first circuit which is closed in response to increase in speed of the vehicle above a value which is less than contract value, and through a second circuit which is opened at a first position in response to increase in the speed of the motive means above a predetermined value which is less than contract value and which is opened in a second position in response to deenergization of said electroresponsive means, means responsive to a stopping operation of the vehicle for maintaining closed said first position, and manually-operable means for closing the second position.

References Cited UNITED STATES PATENTS 1,803,762 5/1931 Marks 187-67 2,565,632 8/1951 Santini 187-29 2,581,297 1/ 1952 Rissler 187-83 EVON C. BLUNK, Primary Examiner.

H. C. HORNSBY, Assistant Examiner. 

1. IN A TRANSPORTATION SYSTEM, A STRUCTURE PROVIDING A PLURALITY OF LANDINGS SPACED IN A VERTICAL DIRECTION, A VEHICLE, MEANS MOUNTING THE VEHICLE FOR MOVEMENT RELATIVE TO THE STRUCTURE IN A PATH HAVING A SUBSTANTIAL VERTICAL COMPONENT FOR SERVICING SAID LANDINGS, COUNTERWEIGHT MEANS FOR SAID VEHICLE FOR BALANCING AT LEAST PART OF THE WEIGHT OF THE VEHICLE, MOTIVE MEANS, TRACTION MEANS COUPLING THE VEHICLE TO THE MOTIVE MEANS, SAID MOTIVE MEANS BEING EFFECTIVE WHEN ENERGIZED FOR OPERATING THROUGH THE TRACTION MEANS TO MOVE THE VEHICLE RELATIVE TO THE STRUCTURE IN AT LEAST ONE DIRECTION ALONG SAID PATH AT A CONTRACT SPEED, AN ENERGIZING CONTROL PATH FOR CONTROLLING ENERGIZATION OF SAID MOTIVE MEANS INCLUDING A FIRST PATH PORTION OPERABLE BETWEEN AN ENERGY TRANSMITTING CONDITION AND AN ENERGY BLOCKING CONDITION, A FIRST CONTROL DEVICE FOR OPERATING THE PATH PORTION FROM ONE TO THE OTHER OF SAID CONDITIONS OF THE PATH PORTION, AND MOTION-RESPONSIVE MEANS RESPONSIVE TO FAILURE OF SAID VEHICLE TO MOVE ABOVE A PREDETERMINED SPEED WHICH IS BELOW THE CONTRACT SPEED OF THE VEHICLE WHEN THE MOTIVE MEANS IS ENERGIZED TO PRODUCE CONTRACT SPEED FOR OPERATING THE CONTROL DEVICE TO MAINTAIN SAID ENERGIZING CONTROL PATH IN CONDITION TO INTERRUPT ENERGIZATION OF THE MOTIVE MEANS. 